摘要:

AbstractA design synthesis procedure is developed for preliminary design of utility systems. Given known steam sources (waste heat and auxiliary boilers) and sinks (heating, process injection, and driver horsepower needs), the algorithm determines the optimal header pressure levels, the distribution of steam turbines in the network, and the steam flows between all devices so as to maximize the real work recovered from the sources. Any number of pressure levels can be accommodated at only modest increase in computational effort.

ISSN:0001-1541    

DOI:10.1002/aic.690300112

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractA mathematical model has been developed to simulate the Texaco downflow entrained‐bed pilot‐plant gasifier using coal liquefaction residues and coal‐water slurries as feedstocks. This model describes the physical and chemical processes occurring in an entrained coal gasifier. The gasification kinetics describes different complex reactions occurring in the gasifier and the hydrodynamics describes mass, momentum and energy balances for solid and gas phases. Temperature, concentration and velocity profiles along the reactor height were obtained by solving the mass, momentum and energy balances. Parameter studies were made to provide a better understanding of the reactor performance for various inlet feed conditions utilizing the

ISSN:0001-1541    

DOI:10.1002/aic.690300113

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractA new method for decomposing irreducible subsets, in the solution of systems of nonlinear algebraic equations, is presented. This method consists of two steps: (1) elimination of the nonlinearity from some of the equations by replacing nonlinear expressions by new variables; and (2) formulation of a problem of smaller dimension by tearing the linear subset of equations. It is shown that these modifications do not change considerably the convergence rate of the Newton‐Raphson and Broyden's methods while reducing the problem's dimension. Computer time reduction up to 80% is demonstrated in the examples solved. An algorithm for elimination of nonlinear expressions, which uses Boolean matrices instead of formula manipulation, is also presente

ISSN:0001-1541    

DOI:10.1002/aic.690300114

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractSolid tracer particles were fed pneumatically through a jet into a fluidized bed to simulate the feeding of solids via a pneumatic transport line into a fluidized‐bed reactor operating in the slugging‐bed mode. The fluidized bed was defluidized instantaneously at different times after the initiation of the tracer particle injection. The bed was then sampled layer by layer to provide the radial and axial concentration profiles of the tracer. Regular and high‐speed movies (1,000 frames per second) were taken to study the operation of the fluidized bed and the phenomena of the gas‐solid two‐phase jet.Experimental results on solid mixing, jet constriction and slugging frequencies, slugging bed height, slug length, jet penetration, and jet half‐angle at three nominal jet velocities of 52, 37, and 25 m/s and corresponding solids loadings are presented. Additional experimental results on jet constriction and slugging frequencies, and slug volume (axial slug size) obtained for a wider range of jet velocities confirm the hydrodynamic trends observed during the tracer particle injection experiments. The results indicate that solids mixing increases, and well‐mixed conditions are reached earlier, with an increase in jet injection velocity. The obtained mixing times were correlated successfully in terms of the excess gas velocity. The experimental data on jet penetration and slug motion were satisfactorily correlated by modified versions of existing theoretical relations. The modifications included the effect of the injected solids on jet penetration and jet half‐angle and also the effect of our semicircular column geometry and single wall‐slug configuration on the obs

ISSN:0001-1541    

DOI:10.1002/aic.690300115

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractPolymeric solutes in jet fuel can serve to increase greatly the droplet size and reduce flammability in fuel sprays created by high‐velocity wind shear. Photographic and spark‐ignition studies show that high molecular weight polyisobutylenes can be effective at levels below 100 ppm, where they cause only slight increases in fuel viscosity. The effectiveness of the polymers increases with molecular weight and is very well correlated by the elongational viscosity of the solution, as measured by the ductless siphon hei

ISSN:0001-1541    

DOI:10.1002/aic.690300116

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractA 5‐cm‐diameter reciprocating plate extraction column has been operated in cocurrent flow. The pressure drop for water flow, and the local and average mass transfer products for the system acetic acid/kerosene/aqueous sodium hydroxide have been measured. Under well‐agitated conditions, the mass average transfer product is predictable by a model, which is also applicable to data reported earlier by Karr for a 2.54‐cm‐diamet

ISSN:0001-1541    

DOI:10.1002/aic.690300117

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractA new experimental method for the measurement of catalyst surface area of supported catalysts has been developed using selective physisorption. The desorption characteristics of a gas are studied separately on the catalyst, the support, and the supported catalyst by carrying out thermal desorption experiments in a continuous flow sorptometer. Differences in the coverage vs. temperature curves, obtained from the thermal desorption experiments, are a measure of the selectivity of the physisorbing gas, and allow calculation of the fraction of total surface area occupied by the catalyst.Two systems have been studied utilizing the thermal desorption with carbon dioxide as adsorbate: potassium carbonate/carbon black and silver/alumina. Supported catalyst surface area was determined for each system; the results were confirmed using physical mixtures of the two components (where the actual area of each component is known) and oxygen chemisorption for the silver/alumina system. The experimental technique allows for straightforward calculation of the catalyst area.

ISSN:0001-1541    

DOI:10.1002/aic.690300118

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractCurrently available group‐contribution methods forTc,Pc, andVcwere evaluated using the Ambrose (1980) critical property data compilation. The Ambrose estimation methods were found to be the most accurate. Linear regression methods were also employed to develop alternate estimation methods which were found to have an accuracy comparable to those of Ambros

ISSN:0001-1541    

DOI:10.1002/aic.690300119

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractA physical model for the very strong intermolecular forces in liquid metal mixtures is proposed, involving the combined effects of ion‐ion, ion‐electron, and electron‐electron interactions plus the charge density effects on the electron kinetic energy. The resulting excess Gibbs energy expression contains a single cross‐energy parameter which must be evaluated either from the eutectic point or from one mixture datum. The applicability of the model is limited to systems without strong specific solvation, but it does effectively predict both negative and positive deviations from Raoult's law, including the asymmetry arising from size differences. Applications are shown for vapor‐liquid, liquid‐liquid and solid‐liqu

ISSN:0001-1541    

DOI:10.1002/aic.690300120

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractMoment analysis is a powerful tool in reactor bed analysis. Weighted moments is a technique which has been introduced to increase the accuracy of moment estimation. The supposed advantage of weighted moments is reevaluated utilizing an optimum truncation point. The resulting coefficient of variation in the moment estimates is shown to be superior to an arbitrary truncation point for all weighting factors. When an optimum truncation point is used, little advantage is observed for weighted moments.

ISSN:0001-1541    

DOI:10.1002/aic.690300121

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY